Grinder/polisher

ABSTRACT

An improved grinder/polisher includes a base having a bowl, a rotating drive plate and a drive plate drive that is adapted to support a platen. The grinder/polisher includes a head configured to support a specimen holder. The head has a first drive for rotational drive of the specimen holder and a second drive for moving the specimen holder toward and away from the drive plate. The head includes a load cell operably connected to the first drive and a counter operably connected to the second drive. The counter is configured to determine movement and the extent of movement of the head toward and away from the drive plate. The grinder/polisher includes a control panel mounted within a housing and including a microprocessor controlled control system having a touch panel or screen.

CROSS-REFERENCE TO RELATED APPLICATION DATA

This application claims the benefit of priority of provisional U.S.patent application Ser. No. 61/074,455, filed Jun. 20, 2008.

BACKGROUND OF THE INVENTION

The present invention relates to a grinder/polisher. More particularly,the present invention relates to an improved grinder/polisher forpreparing samples for examination.

Grinder/polishers are in use in many industries. They are often used toprepare samples of metals, polymers, ceramics or the like for furtherexamination, such as by microscopic examination.

Known grinder/polishers include a sample or specimen holder that isconfigured to rotate relative to a platen that is also configured torotate. In this manner, there are two rotating motions occurringsimultaneously. A slurry, generally abrasive, is injected onto theplaten to provide an abrasive medium for grinding and polishing thespecimen.

The specimen holder is supported for rotation in a chuck. The holder isa flat plate with multiple openings in which the specimens reside. Inone mode, the specimens are locked into the holder and a downward forceby the holder applies a pressure on the platen. As the holder and platenrotate, the pressure applied by the holder (and specimen), along withthe abrasive action of the slurry, results in a grinding and polishingaction on the specimen.

In another mode, the specimen floats within the holder and a plunger ismoved into contact with the specimen to apply pressure to the specimen.Again, as the holder and platen rotate, the pressure applied by theplunger, along with the abrasive action of the slurry results in agrinding and polishing action on the specimen.

Movement of the holder toward and away from the platen is controlled bya drive located in the grinder/polisher head. The drive motor is used toposition the holder and thus the specimen relative to the platen. Onedrawback to known grinder/polishers is that there is no positivepositioning control or mechanism to precisely control the position ofthe holder relative to the platen.

The platen is supported within a bowl. The bowl serves as a repositoryfor debris that is generated during the grinding/polishing operation.Water or another fluid is used to rinse with bowl to clear the debris.It has been found that even with known rinsing systems, debris cancollect in the bowl and cause unsightly and inconvenient accumulation inthe bowl. It has also been found that if a grind is particularlyaggressive, the platen can heat up which, it is believed, can adverselyeffect specimen preparation.

Accordingly, there is a need for an improved grinder/polisher.Desirably, such a grinder/polisher includes an improved illuminationsystem to enhance the visibility of the working area. More desirably,such a grinder/polisher has an improved rinsing/bowl clearing system.More desirably still, such a grinder/polisher has an improved system forpositioning the head and specimen holder and for holding the specimensin position relative to the rotating platen.

BRIEF SUMMARY OF THE INVENTION

An improved grinder polisher includes a base having a bowl, a rotatingdrive plate, a drive plate drive and a control system. The drive plateis adapted to support a platen.

The grinder/polisher includes an improved illumination system to enhancethe visibility of the working area and has an improved rinsing/bowlclearing system. An improved system is also provided for positioning thehead and specimen holder and for holding the specimens in positionrelative to the rotating platen.

In a present embodiment, the head is configured to support the specimenholder. The grinder polisher includes, housed within the head, a firstdrive for rotational drive of the specimen holder (a rotational drive)and a second drive for moving the head and the specimen holdervertically, toward and away from the platen (a height drive).

The head includes a load cell operably connected to the first drive anda counter configured to determine movement and the extent of movement ofthe head toward and away from the platen.

The load cell is adapted to sense contact between the specimen holderand the platen when the second drive is operating in a forward direction(to move the specimen holder into contact with the platen) and to stopmovement in the forward direction upon sensing contact between theholder and the platen. In a present system, in one mode of operation,the control system is configured so that following sensing contactbetween the specimen holder and the platen, the second drive is stoppedand reversed to move the specimen holder away from the platen apredetermined distance. In this operating mode, the specimens are thenpositioned in the holder. The specimens are held in place by fingersduring the grinding/polishing operation. The fingers are extendable fromand retractable into a portion of the head that is rotatable with thespecimen holders. The fingers are configured to contact the specimensand apply a pressure on the specimens to engage the specimens with theplaten.

In a present embodiment the fingers are biased to the retracted positionand means are present for extending the fingers. The fingers are formedfrom a base material having a coating thereon. One suitable coating is aceramic material.

In another mode of operation, the control system is configured so thatthe load cell senses a load generated by contact between a specimen andthe platen and generates a signal to actuate the second drive to operatein a forward direction to move the specimen toward the platen as theload changes. The grinding/polishing operation can be carried out basedupon a predetermined period of operating time or distance moved (e.g.,grinding that has occurred).

The grinder/polisher includes a main drive shaft operably connected tothe specimen holder and operably connected to the load cell, wherein aforce exerted on the main drive shaft provides the sensing of the loadgenerated by contact between the specimen and the platen.

The height drive includes a lead screw for moving the specimen holdertoward and away from the platen. The lead screw is operably connected tothe counter. A carriage and rails are provided for guiding the head andthe specimen holder toward and away from the platen.

The control system is housed, at least in part, in a housing andincludes a microprocessor controlled control system. The control systemincludes a touch panel or screen.

The improved grinder polisher can also include a replaceable bowl linerfor fitting into the bowl. In a present grinder polisher the bowl andbowl liner have a general D-shape to define spaces between the peripheryof the platen and the bowl liner for hand access to the platen. The bowlliner can be transparent and formed from plastic.

The grinder polisher can also include lighting disposed in the headdirected toward the platen and bowl. The lighting is preferably providedby LEDs.

These and other features and advantages of the present invention will bereadily apparent from the following detailed description, in conjunctionwith the claims

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The benefits and advantages of the present invention will become morereadily apparent to those of ordinary skill in the relevant art afterreviewing the following detailed description and accompanying anddrawings, wherein:

FIG. 1 is a perspective view of the improved grinder/polisher embodyingthe principles of the present invention;

FIG. 2 is a front view of the grinder/polisher shown with the headrotated slightly away from the base;

FIG. 3 is a side view of the grinder/polisher;

FIG. 4 is a top view showing the platen and the hand-holds provided bythe D-shaped base and splash guard, the grinder/polisher also shown withthe head rotated slightly away from the base;

FIG. 5 is a close-up view of the platen shown with a user's hand toillustrate access to the platen;

FIG. 6 illustrates one of the fingers extended (by a user's hand) forease of illustration, also noted are the LEDs for work areaillumination;

FIG. 7 is a perspective view showing the platen and a central modespecimen holder in position for operation, also noted is the dispenserportion of the hose (the hose not shown) positioned over the bowl;

FIG. 8 is an illustration of a central mode specimen holder withspecimens mounted therein in the foreground and a single mode specimenholder in the background;

FIG. 9 illustrates the drive plate, showing the openings in the driveplate and also showing, in part, the bowl drain;

FIGS. 10A and 10B are elevational and perspective views of the head(height) drive assembly showing the main shaft and load cell;

FIG. 11 is a perspective illustration of the head with a specimen holdermounted thereto;

FIGS. 12A-B are illustrations of the head showing the height driveassembly and having portions of the head removed for clarity ofillustration;

FIG. 13 is a partial view of the height drive assembly

FIG. 14 is a perspective view of a portion of the rotational driveassembly;

FIGS. 15A-C are perspective and elevational views of portions of thespecimen (rotational) drive and chuck, shown with a specimen holdertherein and the specimen drive assembly shaft and chuck and the specimenholding fingers;

FIGS. 16-17 are elevation and sectional views of the specimen(rotational) drive and chuck;

FIG. 18 is an exploded view of the platen drive and drive assembly;

FIGS. 19-20 are front and sectional views of the control system andhousing, FIG. 20 being taken along the line 20-20 in FIG. 19;

FIGS. 21-23 are bottom and sectional views of the base, FIGS. 22 and 23taken along lines 22-22 and 23-23, respectively in FIG. 21;

FIG. 24 illustrates some of the icons on the control system screen;

FIG. 25 is a partial perspective illustration of the dispenser with thehose extended for rinsing the platen and bowl;

FIG. 26 illustrates removal of the platen;

FIG. 27 illustrates removal of the splash guard;

FIG. 28 illustrates a clear liner for placement in the bowl;

FIG. 29 shows the ready installation of the specimen holder; and

FIGS. 30 and 31 illustrate one of the fingers retracted and extended forgrinding/polishing.

DETAILED DESCRIPTION OF THE INVENTION

While the present invention is susceptible of embodiment in variousforms, there is shown in the drawings and will hereinafter be describeda presently preferred embodiment with the understanding that the presentdisclosure is to be considered an exemplification of the invention andis not intended to limit the invention to the specific embodimentillustrated.

It should be further understood that the title of this section of thisspecification, namely, “Detailed Description Of The Invention”, relatesto a requirement of the United States Patent Office, and does not imply,nor should be inferred to limit the subject matter disclosed herein.

Referring now to the figures and in particular, to FIGS. 1-4, there isshown an improved grinder/polisher 10. The grinder/polisher 10 includes,generally, a base 12, a head 14 and a control panel 16. Unlike knowngrinder/polishers, the casing 18 of the present device 10 is fabricatedfrom a cast material. A present material is a cast aluminum. Knowngrinder/polishers are fabricated from sheet material (sheet metal) or aplastic over a supporting frame. As such, known grinder/polishers can besubjected to vibration, damage due to use and the like. The present castbody (head 14, base 12 and control panel housing 20) provide a stablesupport structure for the grinder/polisher 10, even under aggressivegrinding conditions.

The base 12 houses the platen 22, the platen drive 24, and the fluidsupply and rinse components 26. The base 12 also houses a collectionbowl or basin 28 in which the fluid is collected, as well as debris thatis generated during grinding/polishing.

As will be appreciated, there can be a considerable amount of debristhat is generated during operation, and as such, debris build-up on thebowl 28 can be problematic. In many cases, the debris hardens and isdifficult and time consuming to remove. It has been observed that insome instances, when the debris has been allowed to accumulate too muchand has hardened, it can be almost impossible to remove. At times, theamount of force required to break away the debris is so great, that ithas resulted in damage to these known grinder/polisher bowls.

To alleviate this condition, the present grinder/polisher 10 includes aremovable/replaceable/disposable bowl liner 30 (see FIG. 28). This, ofcourse, resolves the unsightly or even non-functional condition due toover-accumulation by employing a bowl liner 30 that can be removed orreplaced to facilitate cleaning, and that is intended to be disposed of,if necessary, so that a new, functional bowl liner is readily installedon the grinder/polisher 10. A present bowl liner 30 is preferably formedfrom a plastic material and more preferably a transparent plasticmaterial to permit viewing the bowl as needed.

The fluid supply and rinse 26 includes a hose/dispenser assembly 32mounted to the base 12 (see FIGS. 1-4 and 25). The assembly 32 is usedto dispense or spray water into the bowl 28 to provide a water supply tohelp maintain the bowl 28 clear of debris. In a present grinder/polisher10, the hose 34 is a flexible rubber material stored in the base 12. Thehose 34 can be stored in a system (not shown) that permits extending andretracting the hose 34 from the 12 for use. The hose 34 has a wovenmetal sheathing (not shown) to protect the hose 34 and to permitmanipulating and positioning the hose 34 as desired.

A splash guard 36 is integral with the base 12 and extends up from thebase 12, surrounding the bowl 28. The splash guard 36 and the base 12 atthe splash guard 36 integration have a D-shape (as indicated at 37)which provides open corner areas 38 that define hand-holds (see FIG. 5),so that an operator can access the area inside of the bowl 28, withinthe area bounded by the splash guard 36.

The platen 22 is removable and is mounted to a drive plate 40 that isdriven, by a belt 42, from a platen drive motor 43 and form part of theplaten drive 46 (see FIGS. 9, 18 and 21-23). The drive plate 40 andplaten 22 are configured to rotate clockwise or counterclockwise,typically from about 10 rpm to about 500 rpm. A high torque motor 43 isused to assure constant platen 22 speed and torque, regardless of theapplied load.

The drive plate 40 includes openings 44 in the bottom thereof so thatwater can enter up through the drive plate 40 onto the underside of theplaten 22. One preferred platen 22 has fins or spokes (not shown) on theunderside that direct water outwardly. This facilitates cooling theplaten 22 from underneath. It has been observed that when a grind isparticularly aggressive, the platen 22 may tend to heat, which, in turnmay have an adverse effect on the specimen being prepared. Accordingly,platen 22 cooling helps to maintains the platen 22 at a more optimaloperating temperature.

The head 14 supports and rotates the specimens S. The head 14 is mountedto the base 12 by a telescoping support 48. The head 14 contains twodrive systems 50, 52—one drive system 50 for rotation of the specimenholder 84 via the chuck 54, and a height drive system 52 for up and downmovement of the head 14 to move the specimen holder 84 and the specimensS toward and away from the platen 22. The movements, rotational andheight, are provided by the separate drive systems 50, 52.

The rotational drive 50 (see FIGS. 14-17) is configured to rotate thespecimen holder 84 in either a clockwise or counter clockwise direction.In a present grinder/polisher 10, the drive system 50 is a gear 51drive, driven by a motor 53, however, a direct drive, belt drive or thelike can also be used. It will be understood that the head 14 isstationary as the specimen holder 84 rotational drive 50 is operating.The drive system 50 includes a can-like housing 57 that has a gear 55that engages the motor gear 51 to rotate the can-like housing 57.

The height drive 52 (see FIGS. 12-13 and 15) is a precision drive toprecisely position the specimen holder 84 and the specimens S relativeto the platen 22. The height drive 52 is fixedly mounted in the head 14.The present grinder/polisher 10 uses a servomotor 54 that is operablyconnected, by a timing belt 56 to a pulley 58 (driven by the belt 56). Alead screw 60 is mounted to the pulley 58 for rotation with the pulley58. The lead screw 60 is mounted to a fixed (relative to the base 12 andthe support 48) threaded receiving element 62 so that rotation of thelead screw 60 moves the head 14 up and down to move the specimen holder84 toward and away from the platen 22.

The height drive system or assembly 52 includes rails 64 androllers/bearings 66 to provide an underlying support structure and tofacilitate smooth and guided movement of the head 14 as it moves in theup and down motion (by action of the lead screw 60).

In order to precisely locate the head 14 height relative to the platen22 (and the base 12), the height drive 52 includes a lead screw gear 68and counter 70, to count the relative rotation of the lead screw 60 (seeFIGS. 13 and 15). The lead screw gear 68 sits below and is fixedlymounted to the pulley 58 and the lead screw 60. The counter 70 is drivenby a pinion gear 72 that is meshed with the lead screw gear 68. In thismanner, the number of rotations of the lead screw gear 68, which isequal to the number of rotations of the lead screw 60, is counted by therotations of the pinion gear 72, which correlates to the height travelof the lead screw 60. As such, from a baseline position, the height ofthe head 14 (and thus the height or distance of the specimens S from theplaten 22) can be readily determined It will be appreciated from thefigures that the lead screw gear 68 is quite large relative to thepinion gear 72 (and thus the counter 70), and as such there is theability to monitor and control, to a very precise degree, the rotationof the lead screw 60. This in turn provides the ability to preciselycontrol the travel of the head 14 relative to the platen 22.

Although a lead screw 60 and counter 70 arrangement is shown, thoseskilled in the art will recognize other ways in which precise control ofthe specimen S height, relative to the platen 22, can be determined andcontrolled.

The head 14 also includes a load cell 74 (see FIGS. 14-15B). The loadcell 74 is configured to sense the weight load that is placed on therotational drive motor 53 and drive assembly 50 by the specimens S andholder 84 when they are mounted to the drive 50 (at the chuck 80). Theload cell 74 is also configured to determine when the specimen holder84, “hanging” from the motor 53, comes into contact with the platen 22(by sensing an upward force or load differential at the load cell 74).The load cell 74 is disposed above the main drive shaft 76.

Unlike known grinder/polishers, the present grinder/polisher head 14includes integrated lighting 78 (see FIG. 6). In a presentgrinder/polisher 10, light emitting diodes (LEDs) 79 are mounted to thehead 14, to illuminate the holder 84 and specimens S and the platen 22(the work area generally), including the bowl 28. Compact, built-inillumination provides for better viewing of and thus control over thegrinding/polishing process. A present grinder/polisher 10 includes nineLEDs spaced around the periphery of the head 14 for work area/specimen Sillumination. It will be appreciated that the LEDs 79 do not rotate withthe chuck 80 but are stationary as mounted within the head 14.

The chuck 80 is operably mounted to the main drive shaft 76 (see FIGS.15C, 16-17). The chuck 80 is configured for securing the specimen holder84 thereto. The chuck 80 is adapted to receive a drive adapter 82 thatis mounted to the specimen holder 84. One preferred adapter 82 is atapered adapter (see FIGS. 8 and 17) which permits controlling the forceto the bottom of the sample holder 84 to lower the center of gravity. Italso permits readily changing the specimen holder 84 with a single pullof the clamping ring 86.

For the single mode of operation, the grinder/polisher 10 includespneumatically actuated fingers 88 that extend from and retract into thehead 14 to contact the specimens S. In this mode of operation, thespecimens S “float” in the specimen holder 84 (the specimens S are notfixed within the holder 84), and the pneumatically actuated fingers 88hold down the specimen S within the confines of the holder 84, againstthe platen 22.

The fingers 88 are actuated by a pneumatic system (not shown) within thehousing 14. The fingers 88, of course, rotate with the chuck 80 and thespecimen holder 84 to apply a force on the specimens S during operation.The fingers 88 are formed from a metal core, such as aluminum, and canbe ceramic coated (for example, a baked on ceramic) to reduce frictionin the bushing 90 at the head 14 (see FIG. 15B). The core or basematerial of the fingers 88 is selected to provide increased rigidity andstability of the fingers 88.

In the central mode of operation, the specimens S are secured in theholder 84 and the holder 84 is secured in the chuck 80. Because thespecimens S are secured in the holder 84, the fingers 88 (to hold downthe specimens S) are not required for operation.

Referring to FIGS. 1 and 19-20, the control panel 16 is mounted to thehousing 20 (see FIGS. 1 and 16). In a present grinder/polisher 10, amicroprocessor based control system 92 controls the operation of themachine 10. The control panel 16 is a touch screen 94 or plastic/mylaroverlay on a contact-type panel 96. This arrangement prevents theingress of water or other liquids or contaminants into theelectrical/electronics area of the control system 16. One additionaladvantage of the touch screen panel 16 is that icons (see 98 in FIG. 24)can be used or the icons can appear only as applicable to a particularoperating mode. For example, if a particular operating step is onlyapplicable to the single mode of operation, and the single mode ofoperation is entered into system (a single mode button is touched), thenonly icons that pertain to the single mode of operation can appear onthe screen. A stop switch 100 is located on the control panel housing aswell.

In the single mode of operation, the head 14 starts from a home position(an up or retracted position), with the holder 84 in the chuck 80. Theweight load exerted by the specimen holder 84 is sensed by the load cell74.

The holder 84 moves down (the height drive 52 actuates), until itcontacts the platen 22. Contact is determined by sensing a change in theload on the load cell 74 (to a predetermined differential). Once it isdetermined that the holder 84 has contacted the platen 22, downwardmotion is stopped, and the motor 54 reverses to elevate the holder 84(or back off) from the platen 22 a predetermined distance. In a presentgrinder/polisher 10 operation, the head 14 backs off about 2 mm aftercontact. The specimens are then positioned in the holder 84, and thefingers 88 drop down to contact the specimens S to hold the specimens Sin place. The head rotational drive system 50 is actuated and the platen22 commences rotation to grind/polish the specimens S.

In the central mode of operation, the specimens S are fixed in theholder 84. The holder 84 moves down (the height drive 52 is actuated),until a desired force is sensed, and the platen 22 and head rotational50 drives 24, 53 are actuated to rotate the platen 22 and head (torotate the chuck 80 and specimens S). Typically, the drive 50 isactuated for a predetermined period of time to grind/polish thespecimen. The height drive 52 can be actuated (based upon the loadsensed by the load cell 74, and a preset desired load), to move theholder 84 and specimens downward toward the platen 22 aspolishing/grinding progresses and material is removed from the specimen.

It will be appreciated that the microprocessor-based control system 16provides extreme flexibility in operating the grinder/polisher 10. And,in conjunction with the load cell 74 and the lead screw 60/counter 70drive system, the microprocessor-based control system 16 provides a widearray of controls not known in prior grinder/polisher systems.

It will be understood that the grinding/polishing operation (referred toas preparation) can be based upon a desired time of preparation at adesired force. It can also be based upon a desired amount of material tobe removed from the specimen S. For example, the control system 16 canbe set to apply a desired force on the specimen S. As specimenpreparation is carried out, the load on the load cell 74 is sensed, andthe height system 52 motor is actuated to maintain the load within acertain range. The counter 70 is used, to determine the amount ofspecimen S that has been removed, by sensing (counting) the number ofrotations of the lead screw 60 and determining a distance traveled bythe head 14, which corresponds to the amount of material removed fromthe specimen S. Other modes of operation and control will be appreciatedby those skilled in the art.

All patents referred to herein, are hereby incorporated herein byreference, whether or not specifically done so within the text of thisdisclosure.

In the present disclosure, the words “a” or “an” are to be taken toinclude both the singular and the plural. Conversely, any reference toplural items shall, where appropriate, include the singular.

From the foregoing it will be observed that numerous modifications andvariations can be effectuated without departing from the true spirit andscope of the novel concepts of the present invention. It is to beunderstood that no limitation with respect to the specific embodimentsillustrated is intended or should be inferred. The disclosure isintended to cover all such modifications as fall within the scope of theinvention.

1-14. (canceled)
 15. An improved grinder/polisher, comprising: a basehaving a bowl, a rotating drive plate and a drive plate drive, the driveplate adapted to support a platen, the platen being round defining aperiphery and residing in the bowl; a head configured to support aspecimen holder and having a first drive for rotational drive of thespecimen holder and a second drive for moving the specimen holder towardand away from the platen; and a replaceable bowl liner for fitting intothe bowl, the bowl and bowl liner having a general D-shape, whereinspaces are defined between the periphery of the platen and the bowlliner for hand access to the platen.
 16. The grinder/polisher inaccordance with claim 15 wherein the bowl liner is transparent.
 17. Thegrinder/polisher in accordance with claim 15 wherein the bowl liner isformed from plastic. 18-20. (canceled)
 21. An improved grinder/polisher,comprising: a base having a bowl having an other than round shape; around rotating platen supported in the bowl; a specimen holder formoving a specimen toward and away from the platen; and a bowl liner forfitting into the bowl, the bowl liner having an other than round shapeconforming to the bowl, wherein spaces are defined between the peripheryof the platen and the bowl liner for hand access to the platen.
 22. Thegrinder/polisher in accordance with claim 21 wherein the other thanround shape is a general D shape, the liner being configured to conformto the bowl.
 23. The grinder/polisher in accordance with claim 21wherein the bowl liner is replaceable.
 24. The grinder/polisher inaccordance with claim 21 wherein the spaces defined between theperiphery of the platen and the bowl are symmetrical.
 25. Thegrinder/polisher in accordance with claim 21 wherein the bowl liner istransparent.
 26. The grinder/polisher in accordance with claim 25wherein the bowl liner is formed from plastic.